Effect of PPARγ agonist on Aβ phagocytosis in primary microglia. Effect of PPARγ agonist on Aβ phagocytosis in primary microglia. Rat primary microglia were incubated with increasing concentrations of DSP-8658 or pioglitazone in the presence of FAM-Aβ (0.5 μm). After 4 h exposure to Aβ, intracellular levels of Aβ were determined. Both DSP-8658 (A) and pioglitazone (B) enhanced the uptake of Aβ in rat primary microglia in a concentration-dependent manner (mean ± SEM of n = 3, *p < 0.05, **p < 0.01, ***p < 0.001, one-way ANOVA, Tukey's post hoc test). C, Intracellular uptake of Aβ1–42 was confirmed by immunocytochemical staining of Aβ using antibody IC16 and the cell-surface antigen CD11b using antibody MCA711. Scale bar, 10 μm. Rat primary microglia were incubated for 30 min with FAM-Aβ in the presence of 0.3 μm DSP-8658 (D) or 0.3 μm pioglitazone (pio) (E) (mean ± SEM of n = 3). PPARγ mRNA (F) and protein levels (G) in primary microglia transfected with siRNA for PPARγ (mean ± SEM of n = 3, *p < 0.05, Student's t test). Primary microglia transfected with siRNA for PPARγ or nontarget were incubated with DSP-8658 (H) or pioglitazone (I) in the presence of FAM-Aβ (0.5 μm). DSP-8658 and pioglitazone enhanced Aβ uptake at 3 μm in nontarget control siRNA-treated primary microglia, although the same treatments failed to increase Aβ phagocytosis in PPARγ siRNA-treated primary microglia (mean ± SEM of n = 3, *p < 0.05, **p < 0.01, one-way ANOVA, Tukey's post hoc test). Mitsugu Yamanaka et al. J. Neurosci. 2012;32:17321-17331 ©2012 by Society for Neuroscience